Sheave



Feb. 13, 1968 s. GROSS SHEAVE 5 Sheets-She et 1 Filed Nov. 2, 1966 56WGIZVENTOR. 002 055 8Y p33 /5. I firm/ways s. GROSS SHEAVE Feb. 13, 19683 Sheets-Sheet 2 Filed Nov. 2, 1966 "'i ll llu u S. GROSS Feb. 13, 1968SHEAVE 5 Sheets-Sheet 5 Filed Nov. 2. 1966 5 GIgVENTOR if/vaz/e assUnite 3,368,797 Patented Feb. 13, 1968 3,368,797 SHEAVE Seymour Gross,New London, Cnn., assignor to the United States of America asrepresented by the Secretary of the Navy Filed Nov. 2, I966, Ser. No.591,653 6 Claims. (Cl. 254-190) ABSTRACT 6F THE DISCLOSURE A tiltablesheave for a faired towline comprising a continuous loop sectionconsisting of a non-circular track bearing V-shaped sheave segmentswhich are rollably mounted on the track. The track is mounted on theinner one of a pair of concentric rings, the outer ring forming a trackupon which the inner ring can rotate. The plane of the rings istransverse to the plane of the sheave so that transverse movements ofthe towline force the inner ring to move transversely, whereby thesheave is also forced to move transversely and to tilt.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

This invention relates to an improved sheave and especially to animproved marine towing sheave.

In marine towing applications such as the towing of sonar equipmenthoused in a torpedo-like casing at various depths in the ocean, the bulkand weight of the towed body require towing lines of large diameter. Inaddition, the towing lines are frequently covered with fairings toreduce water drag.

The large diameters of towed lines and the presence of fairingstructures do not permit sharp bending of the lines; it is thus requiredthat the sheave over which the line is payed out over the stern have alarge radius of curvature. However, because of the competition for spaceat the stern of a towing vessel and for ease of handling and mounting ofthe sheave, it is desirable to reduce the size of towing sheaves withoutreducing the effective radius of curvature.

A second problem which occurs during the towing of bodies behind shipsinvolves the sideways shifts in position of the towed bodyandconsequently of the towline. If the sheave is fixed in position in avertical plane, the line scrapes against the sides of the sheave andthere is a good possibility that the line may be damaged. It istherefore desirable to have a sheave which is movable transversely aswell as one which tilts to both sides of its vertical position toaccommodate the sideways movements of the towing line in response to thesideways swings of the towed body.

An object of this invention is to reduce the size of a sheave withoutreducing its effective radius of curvature.

Another object is to provide a sheave which accommo dates itself tosideways shifts in the position of a towed object without damage to thetowing line.

Other objects and advantages will appear from the following descriptionof an example of the invention, and the novel features will beparticularly pointed out in the appended claims.

In the accompanying drawings:

FIG. 1 is an isometric front view of an embodiment of the invention, theview being taken from a position above the middle line;

FIG. 2 is an isometric right-side view taken at an angle of about 45from the front;

FIG. 3 is a partial section taken through the sheave and transversetrack; and

FIG. 4 is a partial section showing details of the tilting means for thesheave and the'manner in which the tilting means is mounted to thetransverse track.

FIG. 1 shows an isometric front view of an embodiment of the invention.A tow line (not shown) passes over the segmented sheave 10 which issecured to the inner ring 14 of the tilting means 12 for the sheave 10.The inner ring 14 is rotatable on roller bearings 15 along the outerring 16 so that the sheave 10 can be tilted from its vertical position(see FIG. 4).

The outer ring 16 is secured to and supported by the tilting means mount18 which is slidable along a transverse track 20, and the transversetrack 20 is supported at its ends by a pair of deck-mounting members 22and 24 which are secured to the deck ofthe towing ship at its stem.

The sheave 10 itself consists of a continuous, movable linkage oftowline-bearing sheave segments 26, each of which is mounted on a pairof rollers 28 (see FIGS. 3 and 4), and a pair of spaced parallel tracks30. (A single track may be used, if desired.) The shape of the tracks30, as is evident in FIG. 3, is not circular. However, the radius ofcurvature along the top edge is suflicient to prevent the towline frombeing bent too sharply, but this radius of curvature does not have to bemaintained elsewhere along the track. Thus, the bottom of the track isflattened out and a good deal of weight and space is thereby saved. Thisspace can be used for stowage of the towed body When it is hauled out ofthe water and taken aboard the ship.

The plane of the sheave 10 is defined herein as a plane passing throughthe middle of the sheave 10 from front to back, the front being the viewof the sheave seen in FIG. 1. The plane of the sheave in FIG. 1 istherefore a vertical plane orthogonal to the plane of the drawing. Themaximum tilt or swing of the plane of the sheave 10 in this particularembodiment of the invention is about 30 to each side of the vertical, asis indicated by line 36 in FIG. 4.

The shape of a segment 26 of the sheave is approximately rectangularwhen viewed from the side and approximately V-shaped with flared tipswhen viewed from the front (see FIG. 4). The manner in which the towlinefits into a segment is illustrated in FIG. 4 which shows a cross-sectionof a towline 32 and its associated fairing 34.

The means by which the individual sheave segments are linked permits thesegments to move with respect to each other as they traverse sections ofthe track along which the radius of curvature changes. It should benoted that the individual segments do not necessarily have to be linkedtogether to form a chain, as is the case in this particular embodiment,but could be placed on the track separately, with a mechanical meanssuch as a tongue and groove arrangement provided to prevent them fromfalling off the track along the bottom edge.

In operation, the towline is brought over the sheave from a drum behindthe sheave and attached to the towed body. The latter is lowered intothe water behind the ship and the towline is payed out the requiredamount. Sideways movements of the towed body cause the sheave to respondby tilting and by transverse movements which act to prevent damage tothe towline and its fairings when the towed body is being let out andpulled in.

It will be understood that various changes in the details, materials,and arrangements of parts (and steps), which have been herein describedand illustrated in order to explain the nature of invention, may be madeby those skilled in the art within the principle and scope of theinvention as expressed in the appended claims.

I claim:

1. A sheave for a towline comprising in combination:

a track in the form of a continuous loop;

a plurality of towline-bearing segments movably mounted on the outerperiphery of said track and sufiicient in number to cover the peripheryof said track, the segments also being movable with respect to eachother; and

means for supporting said track, said means for supporting said trackincluding transverse track means for permitting said sheave to be movedtransversely to the normal vertical position of its plane in response tosideways movements of the towline.

2. A sheave as specified in claim 1, each said sheave segment having across-section shaped substantially like the letter V with flared tips,said sheave further including a plurality of wheels, each said sheavesegment being mounted on a pair of said wheels,

said wheels being mounted so as to roll along the outer periphery ofsaid track.

3. A sheave as specified in claim 1, each said sheave segment having across-section shaped substantially like the letter V with flared tips,said sheave further including a plurality of wheels, each said sheavesegment being mounted on a pair of said wheels,

said wheels being mounted so as to roll along the outer periphery ofsaid track.

4. A sheave as specified in claim 3, said track being noncircular inshape but having a sufficient radius of curvature along its upper edgeand side to avoid damaging the towline because of a sharp bend therein.

5. A sheave for a towline comprising in combination:

a track in the form of a continuous loop;

a plurality of towline-bearing segments movably mounted on the outerperiphery of said track and sutlicient in number to cover the peripheryof said track, the segments also being movable with respect to eachother; and

means for supporting said track, said means for sup porting said trackincluding arcuate means mounted transversely to the plane of said trackand movably supporting said track for movement transversely to its planein response to transverse movements of the towline.

6. A sheave as specified in claim 5, said arcuate means comprising apair of concentric rings, the inner ring supporting said track and beingrotatable within the outer ring so that transverse movements of thetowline act to rotate said inner ring thereby tilting said track as wellas moving it transversely.

References Cited UNITED STATES PATENTS 1,552,161 9/1925 Houghton 254l902,802,639 8/1957 Troyer 254-190 FOREIGN PATENTS 1,303,096 7/1961 France.

RICHARD E. AEGERTER, Primary Examiner.

H. C. HORNSBY, Assistant Examiner.

